The present invention relates to novel congeneric, chlorinated, brominated and/or iodinated, fluorinated aromatic compounds having two benzene rings in their base structure.
The present invention also relates to novel processes for preparing congeneric, chlorinated, brominated and/or iodinated, fluorinated aromatic compounds having two benzene rings in their base structure.
The present invention further relates to the use of the novel congeneric, chlorinated, brominated and/or iodinated, fluorinated aromatic compounds having two benzene rings in their base structure.
Polychlorinated diphenyl ethers, biphenyls and diphenylmethanes are still being used as heat transferers, flame-retardant dielectric insulating fluids in high-voltage transformers and capacitors, or as hydraulic oils in mining.
Polybrominated diphenyl ethers and biphenyls are used as flame retardants for plastics. Numerous representatives of these compound classes are, though, highly toxic and/or precursors of highly toxic polychlorinated or polybrominated dibenzofurans or the dibenzo-p-dioxins. Since the compounds are degraded with very great difficulty, if at all, in nature and are also lipophilic, they accumulate in the adipose tissue of organisms and thus also get into the human organism. It is therefore necessary to detect these compounds even only in traces in order to prevent, for example, dangerous contaminations (cf.:    Römpp Online 2003, “Polychlorierte Biphenyle” [Polychlorinated Biphenyls], “PCB-Abbau” [PCB Degradation], “Polybromierte Biphenyle” [Polybrominated Biphenyls], “Schadstoff-Höchstmengen-Verordnung” [German Maximum Harmful Substance Levels Act], “Flammschutzmittel” [Flame Retardants] and “Dioxine” [Dioxins];    Mitchell D. Erickson, “Introduction: PCB Properties, Uses, Occurrence, and Regulatory History”, in Roberston and Hanson (Editors), PCB, The University Press of Kentucky, pages xi to xxviii, 2001;    George M. Frame “The Current State-of-the-Art of Comprehensive, Quantitative, Congener-Specific PCB Analysis, and What We Now Know about the Distributions of Individual Congeners in Commercial Aroclor Mixtures”, in Robertson and Hanson (Editors), PCB, The University Press of Kentucky, pages 3 to 9, 2001;    Hans-Joachim Lehmler, Carolyn P. Brock, Brian Patrick, Larry D. Robertson, “Synthesis of Polychlorinated Biphenyls (PCBs) and Their Metabolites Using the Suzuki-Coupling”, in Robertson and Hanson (Editors), PCB, The University Press of Kentucky, pages 57 to 60, 2001;    Göran Marsh, Jiwei Hu, Eva Jokobsson, Sara Rahm, and Ake Bergman, “Synthesis and Characterization of 32 Polybrominated Diphenyl Ethers”, Environmental Science and Technology, volume 33, pages 3033 to 3037, 1999;    Anders Garå, Kurt Andersson, Carl-Axel Nilsson and Ake Norström, “Synthesis of halogenated diphenyl ethers and dibenzofurans—A discussion of specific isomers available”, Chemosphere; and    Michael Herrmann, Umweltbundesamt, Postfach 33 00 22, 14191 Berlin, Federal Republic of Germany, “UGILEC” August 2002).
The German patent application DE 199 49 950 A1 has already proposed, in quite general terms, the use of chlorinated, brominated and/or iodinated, monofluorinated polycyclic aromatic compounds such as biphenyls, dibenzo-p-dioxins and dibenzofurans                as internal standards which, together with their parent compounds, i.e. the unfluorinated chlorinated, brominated and/or iodinated biphenyls, dibenzo-p-dioxins and dibenzofurans, pass through physical, chemical and/or biological processes and are then detected and/or analyzed together with them or separately from them,        as external standards which, in place of their parent compounds, pass through physical, chemical and/or biological processes for the purposes of calibrating these processes and are analyzed and/or detected separately from the parent compounds, and/or        as model compounds which, in place of their parent compounds, pass through chemical and/or biological processes for the purposes of elucidating the reaction mechanisms and whose reaction products are detected and/or analyzed.        
More specific details on the structure of the chlorinated, brominated and/or iodinated, monofluorinated biphenyls, dibenzo-p-dioxins and dibenzofurans and of their preparation are, though, not disclosed. There is no mention of chlorinated, brominated and/or iodinated, monofluorinated diphenyl ethers and diphenylmethanes.
2-Fluoro-4-bromobiphenyl is a commercial product which can be purchased from Synthon. It is suitable only to a limited extent as a standard for the quantitative analysis of chlorinated, brominated and/or iodinated biphenyls.
The Russian patent RU 2091789 C discloses the use of a mixture of monofluorotetrachlorodibenzo-p-dioxin, monofluoro-pentachlorodibenzo-p-dioxin and monofluoroheptachlorodibenzo-p-dioxin as an internal standard for the quantitative analysis of chlorinated dibenzo-p-dioxins. Specifically, 2-fluoro-6,7,8,9-tetrachlorodibenzo-p-dioxin, 2-fluoro-1,3,4,7,8-pentachlorodibenzo-p-dioxin and 2-fluoro-1,3,4,6,7,8,9-heptachlorodibenzo-p-dioxin are used. The mixture is, though, only of limited suitability for the quantitative analysis of chlorinated, brominated and/or iodinated dibenzo-p-dioxins.
Dihalogenated diphenyliodonium salts such as 4,4′-difluoro-, 4,4′-dichloro-, 4,4′-dibromo- and 4,4′-diiododiphenyliodonium salts are known from the article by F. Marshall Beringer, Robert A. Falk, Marilyn Karniol, Irving Lillien, Giulio Masullo, Marvin Mausner and Erwin Sommer “Diaryliodonium Salts. IX. The Synthesis of Substituted Diphenyl Iodonium Salts”, Journal of the American Chemical Society, volume 81, pages 342 to 351, 1959. Polybrominated diphenyliodonium salts are known from the article by Göran Marsh, Jiwei Hu, Eva Jokobsson, Sara Rahm, and Ake Bergman, “Synthesis and Characterization of 32 Polybrominated Diphenyl Ethers”, Environmental Science and Technology, volume 33, pages 3033 to 3037, 1999. Their use for preparing congeneric, chlorinated, brominated and/or iodinated, monofluorinated diphenyl ethers is not described.
Difluorinated aromatic compounds having at least two benzene rings in their base structure, which are not chlorinated, brominated and/or iodinated, and their use in the analysis of polycyclic aromatic compounds are known from the article by J. T. Anderson and U. Weis, “Gas chromatographic determination of polycyclic aromatic compounds with fluorinated analogues as internal standards”, in Journal of Chromatography A, 659 (1994), pages 151 to 161, or the article by G. Luthe, F. Ariese and U. A. Th. Brinkman, “Retention behaviour of higher fluorinated polycyclic aromatic hydrocarbons in reversed-phase liquid chromatography”, in Chromatographia, January 2004. It is detailed comprehensively therein that the difluorinated polycyclic aromatic compounds have very much greater differences compared to their parent compounds than the monofluorinated polycyclic aromatic compounds, so that they are less suitable as internal standards.